Process for detecting ion concentration

ABSTRACT

A PROCESS FOR DETECTING THE ION CONCENTRATION IN A LIQUID WHEREIN A GIVEN QUANTITY OF AN ION EXCHANGE RESIN WHICH IS RESPONSIVE TO THE ION CONTENT OF A LIQUID BY A CHANGE IN ITS VOLUME IS SUBJECTED TO A WASHING BY A SAMPLE OF THE LIQUID THE ION CONCENTRATION OF WHICH IS TO BE DETECTED AND APPLYING A MECHANICAL MEANS TO DETECT A CHANGE IN THE VOLUME OF THE GIVEN QUANTITY OF THE ION EXCHANGE RESIN TO DETECT THE ION CONCENTRATION OF THE LIQUID WITH WHICH IT WAS WASHED.

Aug. 15, 1972 0. cs. PROSSER 3,634,704

PROCESS FOR DETECTING ION CONCENTRATION Original Filed April 23. 1969 2 Sheets-Sheet 1 lwi'i I INVENTOR DAVID G. PROSSER Vwfw ATTORNEY 5, 1972 o. e. PROSSER PROCESS FOR DETECTING ION CONCENTRATION Original Filed April 23. 1969 2 Sheets-Sheet 2 INVENTOR DAVID S. PROSSER ATTORNEY United States Patent 3,684,704 PROCESS FOR DETECTING ION CONCENTRATION David G. Prosser, Mequon, Wis., assignor to Autotrol Corporation, Milwaukee, Wis.

Original application Apr. 23, 1969, Ser. No. 818,763, now Patent No. 3,574,330, dated Apr. 13, 1971. Divided and this application Sept. 2, 1970, Ser. No. 69,078

Int. Cl. B01d 15/06 US. Cl. 210-25 4 Claims ABSTRACT OF THE DISCLOSURE A process for detecting the ion concentration in a liquid wherein a given quantity of an ion exchange resin which is responsive to the ion content of a liquid by a change in its volume is subjected to a washing by a sample of the liquid the ion concentration of which is to be detected and applying a mechanical means to detect a change in the volume of the given quantity of the ion exchange resin to detect the ion concentration of the liquid with which it was washed.

CROSS-REFERENCE TO RELATED APPLICATIONS This is a division of application Ser. No. 818,763, filed Apr. 23, 1969 now US. 3,574,330, issued Apr. 13, 1971.

BACKGROUND OF THE INVENTION Generally a water softener consists of a tank containing a bed of ion exchange resins through which the water to be treated flows, and the resin serves to combine with those ions in the water that make the water hard. As the water softener is used, the capacity of the ion exchanger to combine with ions becomes exhausted, the exhaustion beginning at the end of the bed where the hard water enters and gradually traveling the length of the bed toward the end where the sof water leaves. Generally, the hard water enters at the top of the tank and the soft water flows out of the bottom. The ability of an exhausted ion exchanger bed to perform its function of combining with ions in hard water can be restored by washing the resin with a selected reagent, and this procedure is generally referred to as regenerating the bed. In most water softeners the softener resin bed is regenerated by pumping brine through it.

While it is possible to determine the need for regenerating the ion exchanger by periodically conducting established chemical tests on the treated water, this is so impractical, particularly for residential water softener installations, as to be unfeasible. Hence, automatic means are needed for regenerating the ion exchanger, preferably at a time of day or night when there will be a minimum demand for soft water.

Prior to the present invention, timing devices such as that shown in US. Patent No. 3,302,467, which issued on Feb. 2, 1967, were commonly used. That timing control operates to regenerate the ion exchanger at preset periodic intervals regardless of the condition of the ion exchanger. At the time of installation of the water softener, the installer must estimate the gallons of softened water that would probably be demanded by the customer, appraise the average hardness of the water, and then he sets the timing mechanism to regenerate the ion exchanger at intervals long before the entire bed of ion exchanger becomes exhausted in an effort to ensure that the customer is never without softened water. This system, while effective, has a number of disadvantages. It is easy to misjudge the time when regeneration is needed and if the period between regenerations is too long, the customer will get soft water only part of the time and will be dissatisfied. To avoid that result, the periodic regeneration of the resin bed, based solely on time, necessitates excessive amounts of salt, because a large safety factor must be calculated to ensure that the bed is never completely exhausted, and then it tends to become burdensome to the customer to maintain an adequate salt supply for the frequent regenerations. If, for any reason, the customer suddenly stops using water, as occurs for example in residential installations when the residents leave for extended vacations, the regeneration of the bed, though unnecessary, proceeds at the pre-set intervals. Finally, it is not unusual for the volume of water used and water hardness to fluctuate widely, requiring repeated service calls to reset the frequency of regeneration.

It is known that some ion exchangers, if washed with water, will reflect the ion content of the water with radical changes in volume. This phenomena is explained and disclosed in Patent No. 2,810,692, which issued on Oct. 22, 1957. It has remained for the present invention to pro vide a feasible, workable and practical means for utilizing that phenomenon to determine the need for and to effect regeneration of the softener ion exchanger automatically only when the softener ion exchanger becomes exhausted. Thus the present invention obviates the disadvantages of the time controlled regeneration systems, to enhance the practical success of Water softener installations, particularly installations which are not attended by trained and skilled personnel.

SUMMARY OF THE INVENTION The present invention relates to a method of sensing ion concentration in a liquid utilizing an ion exchanger that swells or shrinks in volume when washed by the liquid in response to the ion concentration in that liquid. More specifically the invention resides in a process according to which a measured quantity of ion exchanger is placed in a sensing chamber, a sample of liquid is admitted into said sensing chamber to wash said ion exchanger, a plunger in said chamber is moved into engagement with said ion exchanger to measure its volume; said plunger is withdrawn out of contact with said ion exchanger, and said ion exchanger is regenerated by washing it with a regenerating reagent.

The foregoing process ensures that the ion exchanger will be unimpeded in its growth during that portion of the cycle when it swells. This has been found to be critical to the successful practical utilization of those ion exchanges in a sensor for sensing the ion content of a liquid. As a result of this process, the ion exchanger reliably senses the condition of the sampled liquid with calculable accuracy.

The invention may be practiced with apparatus which includes a sample sensing chamber that can serve as a receptacle for an ion exchanger that has a reciprocable plunger seated inside of its top with an extension projecting out of the sample sensing chamber for controlling and sensing the movement of the plunger; a liquid sample inlet which contains a valve and which is adapted to emit the liquid into the chamber laterally at a plurality of vertically spaced locations, and a liquid outlet which is adapted to receive liquid in said sample sensing chamber at a plurality of vertically spaced locations.

In addition this apparatus provides for a horizontal how of liquid through the ion exchanger to ensure a thorough immersion of the ion exchanger in the liquid and to agitate the ion exchanger so that it does not become compacted.

The plunger is also held away from the ion exchanger at all times, except when sensing its volume, so that the ion exchanger will not coalesce or fracture and will not be inhibited from repeatedly seeking that volume that precisely reflects the condition of the water sample.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a view in front elevation of a sensor control embodying the present invention with portions broken away to reveal internal functioning structure,

FIG. 2 is an exploded view in perspective of an output gear assembly from the sensor control shown in FIG. 1,

FIG. 3 is an exploded view in perspective of the output gear assembly shown in FIGS. 1 and 2, as viewed from the bottom of FIG. 2,

FIG. 4 is an exploded diagrammatic view of the gear trains and assemblies in the sensor control shown in FIG. 1, and

FIG. 5 is an exploded view of the rotary control assembly employed in the sensor control shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus hereinafter described can be advantageously utilized in practicing the novel process of this invention.

As can be seen in FIG. 1, the mechanism of a sensor control is enclosed in a rectangular housing 1, the cover (not shown) of which is removed to reveal the mechanism. The rectangular housing 1 would be mounted on top of a water softener tank on the end of a valve control assembly such as is shown in my co-pending application, Ser. No. 739,539, filed June 24, 1968, and entitled Softener Control Assembly, it being the function of the present mechanism to transmit driving force to the mechanism shown in that application for operating valves that control the flow of this water to be treated and of the regeneration fluid. Mounted to the bottom of the housing 1 by means of screws (not shown) is a sample sensing chamber 2, which is shown in section to reveal its interior, and which contains an ion sensitive resin 2a which shrinks when Wetted with hard Water.

The sample sensing chamber 2 is a hollow, rectangular shaped object made of a section of plastic rectangular tubing forming the vertical sidewalls and molded plastic top and bottom members 21 and 23, respectively, which are assembled together by the mounting screws (not shown) that extend vertically through the corners of those three pieces and into the housing 1. A flexible sampling tube 3 is suspended by a threaded sleeve 4 on a tubular fitting 4a that protrudes from the bottom of the sample sensing chamber 2, and the sampling tube 3 passes through an adjustable gripping seal 5 that is screw mounted in an upper wall 6 of a water softener tank. A weighted intake nozzle is fastened on the end of the sampling tube 3 that is suspended in a bed of softener ion exchanger 120 inside the softener tank. An exhaust tubing 7 is fastened by a threaded sleeve 8 to a tubular fitting 8a that protrudes from the bottom of the sample sensing chamber 2 on the opposite side from the sampling tube 3.

A valve assembly 11 normally closes the mouth of the sampling tube 3 and has a valve stem 12 that extends upward out of the sample sensing chamber 2. Inside the sensing chamber 2 a vertical tube 13 which is vented with a plurality of vertically spaced transverse slots or openings houses a needle 14 on the end of the valve stem 12. A pair of O-ring seals 15 and 16 are fixed in annular seats at opposite ends of the tube 13. The valve stem 12 is sealed through the upper O-ring 16, and the needle 14 is inserted snugly through the lower O-ring to close the valve assembly 11. To open the valve assembly 11, the valve stem 12 is lifted, withdrawing the needle 14 from the lower O-ring 16. A vertical drain tube 24 that is vented with a plurality of transverse slots or openings extends from the inner mouth of the tubular fitting 8a which opens outwardly into the exhaust tubing 7, to the ceiling of the interior of the chamber 2. Thus, fluids introduced to the chamber 2 through the valve assembly 11 will tend to flow horizontally across the chamber 2 into the vertical drain tube 24 and then down into and out through the exhaust tubing 7.

A flexible diaphragm 17 extends across and seals the top of the interior of the sample sensing chamber 2. The diaphragm 17 is a soft rubber membrane that is sealed about its peripheral edges between the tops of the lateral walls and the top piece 21 of the sample sensing chamber 2 and it passes beneath a mechanical sensor in the form of a plunger 18, to which it is screw fastened. A compression spring 19 urges the plunger 18 downwardly. One end of the compression spring 19 bears against a spring seat 20 in the plunger 18, and the other end of which bears against the top 21 of the sample sensing chamber 2. A plug 22 is screw fitted in an opening through the floor piece 23 of the sample sensing chamber 2 so that the sample sensing chamber 2 may be opened without dismantling it.

The mechanism shown in the rectangular housing 1 in FIG. 1 is most easily described using the exploded diagram in FIG. 4. An electric drive motor 25 is mounted on the outside surface (not shown) on a back wall '26 of the rectangular housing 1 to provide apower source for the entire mechanism of the sensor control, and its drive shaft 27 projects through a bearing (not shown) in the back wall 26 of the rectangular housing 1. The drive shaft 27 has a main drive pinion 28 mounted on its adjacent the inside surface of the back wall 26, and the shaft 27, and pinion 28 are continuously driven by the motor 25. The electric motor 25 is also the prime mover for the Softener Control Assembly of the mentioned copending application of that title, that controls the valves of the softener, or of any other mechanism that is to be driven through the sensor control. The motor 25 is a continuously operating, low speed motor 25 and the mechanism to be disclosed determines when the motive force of the motor 25 is to be transmitted to the Softener Control Assembly or other mechanism to be driven by it, and it serves as a transmission for that motive force. The main drive pinion 28 simultaneously drives four gear trains 29, 30, 31 and 32, which share some common elements, though each train 29-32, performs a specific end function distinct from the others.

The sampling gear train 29 has a spur gear 33 engaged with the main drive pinion 28 with a reduction pinion 34 formed on its hub. The reduction pinion 34 drives a second spur gear 35 that has a reduction pinion 36 on its hub, which simultaneously drives two spur gears 37 and 38, the latter gear 38 operating only in the sampling return gear train 30. The spur gear 37 that is driven by the reduction pinion 36, has a reduction pinion 38 on its hub, and this reduction pinion 39 engages a drive gear segment 40 that forms a part of a rotary control assembly 41, which is illustrated in an exploded view in FIG. 5.

The sampling return gear train 30 shares the spur gears 33 and 35 and their respective reduction pinions 34 and 36 with the sample gear train 29, and has in addition the mentioned spur gear 38 with an extended hub 42 that has a pinion 43 formed on top of it. The extended hub 42 of the return spur gear 38 passes through the hollow center of an annular hub 44 that is formed on the drive gear segment 40. The sampling return spur gear 38 is rotatably mounted on the back wall 26 of the rectangular housing 1 and it rotatably supports the drive gear segment 40 on an annular collar 45 that is formed on the upper surface of the spur gear 38.

The rotary control assembly 41 is, among other things, a unique form of rotary mechanical amplifier. In addition to the drive segment 40, referred to above, the rotary control assembly 41 also includes a trigger gear segment 46 that has for a hub an annular ring 47, which fits rotatably about the hub 44 of the drive gear segment 40. The drii': segment 40 is a circular gear segment 40, the

ends of which are separated by a short gap 48, and the trigger segment 48 is provided with a shorter gear segment 46 that has the same pitch diameter and tooth configuration as the drive gear segment 40. A circular bias spring 49 fits around the annular ring 47 of the trigger segment 46 and has one end hooked about a book 50 projecting from the drive segment 40 and its other end hooked on a hook 50a projecting from a trigger segment 46. A pair of limit arms 51 project radially from the hub 44 of the drive segment 40 through slots 113 in the tubular hub 47 of the trigger segment 46 to limit the rotational movement of the trigger segment 46 with respect to the drive segment 40, and the arms, incidentally, also restrain the bias spring 49 axially to hold it in place. This assembly utilizes the funtcional elements mutually to restrain each other so that no additional screws, rivets or other assembly members are needed. The tension of the bias spring 49 is such and the hook 50 on the drive segment 40 and hook 50a on the trigger segment 46 are so located that the trigger segment 46 is normally biased to a position immediately adjacent to one end of the gap 48 between the ends of the drive segment 40. The trigger segment 46 has a trigger member 52 projecting horizontally it, as viewed in FIG. 1, and a radial trigger member 53 etxending outwardly from it. When the drive segment 40 is at rest with the pinion 39 turning freely in the gap 48 between its ends, either the trigger member 52, or the trigger member 53 may be engaged to overcome the bias spring 49 and rotate the trigger segment 46 into the gap 48 between the ends of the drive segment 40.

The slots 113 define the amount of movement of the trigger segment 46 relative to the drive segment 40, and when one of the triggers 52 or 53 moves the trigger segment 46, it moves the trigger segment 46 to the limit of its relative motion. Thus the trigger segment 46 has two positions relative to the drive segment 40, one at each end of its relative motion, and in each it is in alignment with the drive segment 40. When the trigger segment 46 is in a position wherein it spans the gap 48, it engages the reduction pinion 39 on the spur gear 37, which will rotate the drive segment 40 by means of the trigger segment 46 until the reduction pinion 39 is in direct driving engagement with the drive segment 40. Then the trigger segment 46 can be released and rotated back to its normal position by the bias spring 49. A relief slot 116 is cut in the trigger gear segment 46 to allow the trigger segment 46 to flex. Since the trigger segment is made of a resilient plastic, it can thus be formed to flex under strain. Hence, if the trigger segment 46 is not in perfect alignment with the drive gear segment 40, preventing the drive pinion 39 from meshing immediately with it, the gear teeth will not be damaged. This permits much larger tolerances in the manufacturing specifications with resulting reductions in costs.

A semi-circular collar 54 extends axially from the top end of the hub 44 on the drive segment 40 and on one end of the collar 54 an arcuate gear rack 55 is formed. A linearly reciprocably slidable cam member 56 is located adjacent to the collar 54 and it has a linear gear rack 57 on its upper surface that can be engaged by the arcuate gear rack 55 on the collar 54 as the collar 54 rotates with the drive segment 40. When the arcuate gear rack 55 engages the linear gear rack 57 on the cam member 56, it drives the cam member 56 to the left, as viewed in FIG. 1, and the linear gear rack 57 is held into engagement with the arcuate gear rack 55 by an extension spring 58, one end of which is fastened to the end of the cam member 56 and the other end of which is anchored to a post 59 projecting from the back wall 26 of the housing 1. After the arcuate gear rack 55 has been rotated out of engagement with the linear gear rack 57 on the cam member 56, the linear gear rack 57 rides on the smooth surface of the collar 54 until the end of the collar 54 is rotated past it. When the collar 54 thus releases the linear gear rack 57, the rack 57 is pulled into engagement with the counter rotating pinion 43 on the top of the hub 42 of the return spur gear 38, which drives the cam member 56 back to its extreme position on the right.

The output gear train 31 shares with the timing gear train 32 a spur gear 60, which is driven by the main drive pinion 28. The spur gear 60 has a reduction pinion 61 on its hub, and the reduction pinion 61 drives a second spur gear 62 which has a reduction pinion 63 on its hub. A circular output gear segment 64 is rotatably mounted in the housing 1, and it is engaged by the reduction pinion 63. The output segment 64 is part of a rotary output assembly 65 that is illustrated in exploded view in FIGS. 2 and 3.

The output gear segment 64 has an extended, hollow tubular hub 66 projecting axially out of the rectangular housing 1 with an indicator arrow 67 formed across its top surface and knurled grip portion 68 about its top end. The hollow hub 66 fits rotatably about a portion of a cylindrical journal bearing 69 that is anchored to the back wall 26 of the housing 1 and that projects from the back wall 26 into the housing 1. The journal bearing 69 rotatably mounts an output shaft 105. A compression spring 70 is seated in a spring seat 106 in the drive shaft 105 and bears against the inside of the hub 66, which is restrained in its axial movement by the inside of a front wall (not shown) of the rectangular housing 1. The compression spring 70 tends to hold the output segment 64 into engagement with the reduction pinion 63 formed on the hub of the spur gear 62, so that the hub 66 of the output seg ment 64 may be manually depressed to release the output segment 64 which then may be manually rotatably adjusted free of engagement with the spur gear 62. Rectangular keys 108 and 107 extend radially from opposite sides of the output shaft 105 to slide in grooves 108 and 109 formed on the inside of the hub 66. Thus the rotational movement of the output gear segment 64 is transmitted to the output shaft 105, which conveys that movement through the journal bearing 69 outside of the housing 1 to the mechanism (not shown), such as that disclosed in the co-pending application, Ser. No. 739,539, filed June 24, 1968, and entitled Softener Control Assembly.

The rotary output assembly 65 embodies the same type of unique rotary mechanical amplifier as the rotary control assembly 41. Hence, what has been said of the operation and capabilities of the control assembly 41 applies as well to the corresponding structure in the output assembly 65. The output segment 64 is a circular gear segment 64 with a small gap 71 between its ends. A trigger gear segment 72, which also is a circle segment 72 and which has the same pitch diameter and gear configuration as the output segment 64, has an annular ring 73 for a hub that forms a rotating fit about the hub 66 on the output segment 64. A circular bias spring 74 fits about the annular ring 73, and one of its ends engages a hook 75 on the trigger segment 72 and the other end is anchored to a hook 751: on the output segment 64. The bias spring 74 is restrained beneath a pair of limit arms 76 that radiate from the hub 66 of the output segment 64 through slots 77 in the annular ring 73 above the trigger segment 72, and the limit arms 76 serve to limit the amount of relative rotational movement of the trigger segment 72 with respect to the output segment 64. A trigger 78 projects from the trigger segment 72 so that it may be engaged by some external device to rotate the trigger segment 72 relative to the output segment 64 against the bias spring 74. Normally the trigger segment 72 is held adjacent to one end of the gap 71 provided between the ends of the output gear segment 64, but when the trigger segment 72 is actuated by engaging the trigger 78, the trigger segment 72 rotates into a position above the gap 71 so that the reduction pinion 63 can mesh with the trigger segment 72 and, through the trigger segment 72, drive the output segment 64 until it meshes directly with the output gear segment 64. When the pinion 63 is enmeshed with the output segment 64 the trigger segment 72 is released to return to its normal position. The trigger segment 72 is provided with a relief slot 115 that corresponds in structure and function to the relief slot 116 in the trigger gear segment 46 of the control assembly 41.

The sensing plunger 18 in the sample sensing chamber 2 shown in FIG. 1 has a rod 79 extending from it and projecting out of the sample sensing chamber 2 upwardly into the housing 1. An arm 80 extends from the end of the rod 79 and has a latch 81 on its upper end that is positioned adjacent to the tubular ring 73 with the latch 81 being disposed above the trigger 78 on the output trigger gear segment 72, as viewed in FIG. 1. Thus the latch 81 will reciprocate with the plunger 18 to move into and out of the path of the trigger 78 on the trigger gear segment 72. A cam follower 82 projects outwardly from the arm 80 on the rod 79 of the plunger 18 to ride on a cam surface 83 over the top of the cam member '56. The left end of the cam surface 83 is relatively low but it rises sharply to the right before leveling off, so that as the cam member 56 is driven to the left the plunger 18 is hoisted to the top of its stroke in the sample sensing chamber 2 and the latch 81 is positioned above the trigger 78 of the trigger gear segment 72. When the cam member 56 moves to its sensing position at the extreme right, the cam surface 83 releases the cam follower 82 and the plunger 18, which is then driven downward by the compression spring 19. If the movement of the plunger 18 in the chamber 2 is not obstructed, the latch 81 will engage the vertical trigger 78 and pull the trigger gear segment 72 against the bias spring 74 into a position wherein it spans the gap 71 between the ends of the output gear segment 64 to engage the reduction pinion 63.

The last gear train to be described is the timing gear train 32. The timing gear train 32, as was mentioned, shares the spur gear 60 and reduction pinion 61 with the output gear train 31, and the reduction pinion 61 drives a first spur gear 84. A reduction pinion 85 on the hub of the first spur gear 84 engages a second spur gear 86, which also has a reduction pinion 87. The reduction pinion 87 on the second spur gear 86 engages a third spur gear 88 to drive a timing gear 89 through a reduction pinion 90 on the hub of the third spur gear 88. The timing gear 89 makes one revolution each 24 hours, and it is mounted to be manually set to the time the mechanism is put into operation. An annular collar 91 is mounted on the under side of the timing gear 89 and on one end of the annular collar 91 an extension 92 projects approximately radially outwardly toward the periphery of the timing gear 89. This radial extension 92 of the annular collar 91 is shaped and positioned so that it can engage the trigger 52 projecting from the trigger segment 46 in the control assembly 41 to drive the trigger segment 46 so that the gear segment thereof is positioned across from the gap 48 that is provided between the ends of the drive gear segment 40. The resulting rotation of the drive segment 40 as has been described drives the cam member 56 which controls the sensing and sampling of the water being treated in the softener tank 6.

The sampling valve assembly 11 has a rectangular extension portion 93 on the valve stem 12 that has a guide slot 94 in it, through which a guide post 110 projecting from the back wall 26 of the housing 1 extends to guide its reciprocating travel. On the end of the extension 93 of the valve stem 12 a cam follower 95 projects outwardly through a slotted cam groove 96 in the cam member '56. The left two-thirds of the slot cam groove 96 is horizontal, but in the right one-third, the cam groove 96 rises sharply to a brief plateau at the right end, so that as the cam member 56 moves to the left, the valve stem 12 and needle 14 are raised rapidly during the last third of its travel to open the sampling valve assembly 11. This allows a sample of fluid from the sampling tube 3 to enter the sample sensing chamber 2 while the lifted to its highest position.

The sample sensing chamber 2 is charged with a quantity of ion exchange resin 2a, such as those disclosed in US. Pat. No. 2,810,692. When the charge of ion exchange resin 2a in its normal state (as defined below) is washed with hard water, it shrinks radically. To regenerate the charge of ion exchange resin 2a, which may be referred to as the sensing ion exchanger 2a, after it has been exhausted by the hard water, it is washed with brine, which has the effect of further shrinking the volume of the sensing ion exchanger 2a. When the sensing ion exchanger 2a is washed with soft water after it has been regenerated, it swells radically to its maximum volume, which is here considered to be the normal volume of the sensing ion exchanger 2a.

There are a number of ion exchangers that manifest radical volume changes, either swelling or shrinking when Washed with liquids containing concentrations of ions. It has been discovered that if these ion exchangers are to be used to sense ion concentrations, it is essential that these ion exchangers not be confined when subjected to the particular conditions under which they would grow or swell. If these ion exchangers are confined when they would grow, some manifest a fracturing of the granules and the granules in others tend to coalesce, so that in either case the usefulness of the ion exchanger may be destroyed. Thus it is a significant aspect of the present invention that the sensing ion exchanger be relieved of the pressure of the plunger 18 except during the brief period of sensing, and it is also significant that the flow of the liquid samples and the regenerating liquid is horizontal so as to agitate the sensing ion exchanger 2a and avoid any substantial vertical fluid pressure against the sensing ion exchanger 2a.

It is the function of the sensor control of the present invention to sample the water in the water softener periodically to determine whether the softener ion exchanger 120 requires regeneration. Important to the practical operation of such a periodic sensing device is the level in the softener tank 6 from which the sample is taken. The softener ion exchange resins 120 begin to exhaust at the top where the hard water enters, and the exhaustion progresses down toward the bottom. The water softener remains effectively operative until virtually the entire bed of softener resin 120 is exhausted. The sampling ought to be taken at such a level in the softener resin 120 bed that sufficient unexhausted softener ion exchange resin 120 remains below the sampling level to last until the next succeeding sampling in the event that exhaustion has proceeded to a point immediately above where the sample is taken, but has not gotten quite to the level of the sampling point. Since the level at which the sample should be taken depends upon the hardness of the Water and the volume of water used, the sampling level may be expected to vary with each installation, and thus it is desirable to be able to set the sampling level at the time and place of installation after surveying the determining factors. It is important, therefore, that the sampling level be readily adjustable.

To permit such adjustment adjustable seal 5 is provided. The seal 5 has an outer member 97 which is a tubular plug 97 screw fitted in a threaded hole through the upper wall 6 of the softener tank. The outer member 97 has a top half 98 of its hollow interior of the plug 97 that is cylindrically shaped with a threaded portion 99 at the opening and a bottom half 100 of the hollow interior of the plug 97, the interior diameter of which tapers to its smallest dimension at its bottom end.

The seal 5 also includes a tubular inner member 101 that is telescoped inside of the outer member 97. The inner member 101 has an enlarged head portion 102 on top with a threaded portion 103 of reduced crosssectional dimension beneath it. A smooth cylindrical portion 104 is located below the threaded portion 103 to fit plunger 18 is within the converging bottom half 100 of the interior of the outer member 97 The inner and outer members 97 and 101 of the sealing plug are made of a commercially available acetal homopolymer and the sampling tube 3 is a purchased polyethylene tube. The tapered inside diameter 100 of the outer member 97 is formed to slide against the cylindrical outer portion 104 of the inner member 101. The two surfaces 100 and 104 cooperate on an inclined plane or wedge principle as the inner member 100 is turned into the outer member 97 so that the thinner inner member 101 is constricted. Alternatively, the outer surface 104 of the inner member 101 could be tapered and the inner diameter 100 of the outer member 97 made uniform, and the same result could be achieved. r, both surfaces 100 and 104 could be tapered, though the angles of the surfaces should differ to prevent excessive frictional engagement between them.

As the threaded portion 103 of the inner member 101 of the present embodiment is turned into the threaded interior portion 99 of the outer member 97, the cylindrical surface 104 of the inner member 101 is driven into the tapered diameter portion 100 of the outer member 97. The cooperation of the sliding surfaces 100 and 104 of the outer and inner members 97 and 101 constricts the inner member 101. As the inner member 101 constricts, it tightens about the polyethylene sampling tube 3 until it tightly clamps the tube 3.

The weighted intake nozzle on the end of the sampling tube 3 may be raised or lowered in the softener tank by turning the gripping plug 101 out of the sealing plug 97 so as to loosen the fit of the tapered portion 104 of the gripping plug 101 about the sampling tube 3. When the sampling tube 3 is thus loosened, it may be pulled or pushed through the hollow interior of the gripping plug 101, until the intake nozzle 10 reaches the desired height. When the nozzle 10 is at the desired level the gripping plug 101 is turned down snugly into the sealing plug 97 until the sampling tube 3 is gripped tightly in place. The heavy nozzle 10 is actually buried in the softener ion exchange resin 120 but the ion exchange resin 120 presents no obstacle to the lowering of the nozzle 10 because during regeneration of the resin 120 is cleaned by flowing water up through the bed from bottom to top and this agitates and loosens the bed sufficiently to allow the nozzle 10 to find its lowest level.

The last spur gear 60 shared by the timing train 32 and the output train 31 also drives an indicator gear 111 which is mounted near the top of the housing 1 so that it projects into an opening 112 in the top lateral wall of the housing. The purpose of the indicator gear 111 is to tell an observer at a glance whether or not the sensor control mechanism is operating. When the sensor control of the present invention is in operation, the drive motor 25 turns continuously, driving the main drive pinion 28 and the reduction gear trains 29, 30, 31 and 32 continuously also.

OPERATION To set forth the operating cycle in logical sequence, start with the drive gear 40 of the rotary control assembly 41 rotated to a position where the pinion 39 is turning freely in the gap 48 between the ends of the drive segment 40 and the drive segment 40 is stationary. Also begin with the output segment 64 rotated to a stationary position where the pinion 63 is turning freely in the gap 71 between the ends of the output gear segment 64. Finally, assume that the trigger gear segment 46 in the rotary control assembly 41 and the trigger segment 72 in the rotary output assembly 65 are resting in their normal positions. Of course the weighted intake nozzle 10 has been adjusted to the desired sampling level location in the softener resin 120 bed. The sample sensing chamber 2 contains a measured charge of cation exchange sensing resin 2a of the sort disclosed in US. Pat. No. 2,810,692, and the needle 14 is sealed securely through the O-ring of 10 the sampling intake valve assembly 11. Hard water enters the softener tank 6 at the top and the soft water flows out of the bottom of the tank 6, and the tank 6 is thus filled with water under a normal water pressure of the system in which the softener is being used.

As the drive motor 25 drives the four reduction gear trains 29, 30, 31 and 32, only one of the reduction gear trains, the timing gear train 32, is performing a function at all times and it is rotating the timing gear 89 at a rate that provides one complete revolution every 24 hours. Most of the time the other three gear trains 2931, viewed in terms of an ultimate accomplishment, are simply idling. Assume that the collar 91 with its radial extension 92 on the timing gear 89 is positioned to initiate a sampling at 2 oclock in the morning. For purposes of description, assume that the operation begins moments before 2:00 am. The radial extension 92 of the collar 91 would be seen to approach engagement with the trigger 52 on the trigger gear segment 46 of the rotary control assembly 41. As the timing gear 89 continues to move past 2:00 a.m., the radial extension 92 of the collar 91 engages the trigger 52 and drives the trigger gear segment 46 into a position wherein it spans the gap 48 between the ends of the drive segment 40 where it is engaged by the rotating pinion 39. When the control drive pinion .39 drives the trigger segment 46, the trigger segment 46 pulls the drive segment 40 into engagement with the pinion 39, which then directly drives the drive segment 40 rotating it until the pinion 39 again reaches the gap 48. As the drive segment 40 rotates, the arcuate gear segment 55 on the collar 54 projecting from the top of the hub 44 of the drive segment 40, which was already engaged with the rack 5,7 on the top of the cam member 56, drives the cam member 56 to the left in the drawing, and then rotates past engagement with the linear cam rack 57 so that the cam rack 57 rests on the collar 54.

With the cam member 56 driven to its left most position, the cam follower 95 on the extension 93 of the valve stem 12 has followed the cam groove 96 to its highest point, lifting the valve stem 12 and the needle valve 14 to open the valve 11 to allow a sample of water from the softener tank 6 to flow up through the sampling tube 3 into the tube 13 in the sample sensing chamber 2. The water sample is sprayed out of the tube 13 through its vertically spaced openings and it thoroughly washes and agitates the sensing ion exchanger 2a as it flows across the chamber 2 and enters the drain tube 24 through its many vertically spaced openings to flow out of the chamber 2. After the collar 54 has rotated past the linear rack 57, the meshing spring 58 draws the rack 57 into engagement with the cam return pinion 43, which, rotating in the opposite direction from the drive segment 40 of the control assembly 41, drives the cam member 56 back to the right end of its stroke.

This return of the cam member 56 to the right end of its stroke forces the cam follower 95 on the extension 93 of the valve stem 12 downward, driving the end of the needle valve 14 through the O-ring 15 to close the sample intake valve assembly 11. As the cam member 56 reaches the right end of its reciprocating travel, the cam surface 83 drops off sharply, releasing the cam follower 82 on the shaft of the sensing plunger 18, allowing the compression spring 19 to drive the plunger 18 down against the resin 2a within the sampling chamber 2. If the sample of water from the softener tank 6 that wets the cation exchange resin 2a in the chamber 2, is soft, the cation exchange resin 2a will manifest its normal maximum volume and the travel of the plunger 18 into the sensing chamber 2 will be obstructed and stopped. However, if the water sample is hard, the cation exchange resin 2a will shrink allowing the plunger 18 to drop under the impetus of the compression spring 19 to the bottom of its stroke.

When the output segment 64 is in the position specified so that its drive pinion '63 is rotating freely in the gap 71 between the ends of the output gear segment 64 the trigger 78 on the trigger segment 72 is in the position shown in FIG. 1 immediately beneath the latch 81. Hence, when the plunger 18 is allowed by the shrunken resin 2a in the chamber 2 to drop down, the latch 81 engages the trigger 78 pulling it downwardly with the force of the compression spring 19 to drive the trigger segment 72 into its actuated position in the gap 71 between the ends of the ouput gear segment 64 so that it can engage the output drive pinion 63. The output drive pinion 63 then begins to rotate the output segment 64, first through the trigger segment 72 and then directly as it comes in mesh with the output gear segment 64.

Meanwhile, the drive segment 40 of the control assembly 41 has continued its rotation under the impetus of the pinion 3-9, until it brings the arcuate rack 55 back into engagement with the linear rack 57 on the cam member 56 and drives the cam member 5 6 to the left sufliciently to cause the cam follower 82 to ride upwardly on the output cam surface 83. The movement of the follower 82 on the cam surface 83 lifts the plunger 18 from the top of the cation exchange resin 2a in the chamber 2. This is a significant aspect of the invention because the plunger 18 thus releases the cation exchange resin 20: to allow the cation exchange resin to seek its natural volume determined by the ion concentrations of the liquids that have wetted it. Thus as soon as the cam member 56 has been driven sufficiently far to the left to thus raise the plunger =18, the drive segment 40 of the control assembly 41 completes one rotation with the pinion 39 once again turning freely in the gap 48 between the ends of the drive segment 40.

While the drive segment 40 of the control assembly 41 is returning the cam 56 to its normal, central position to hold the plunger 18 off of the sensing ion exchanger 2a, the output segment 64 on the output gear assembly 65 is rotating, transmitting the drive force of the motor to the control mechanism of the mentioned co-pending application, Ser. No. 739,539, filed on June 24, 1968, and entitled Softener Control Assembly which closes the valves for the hard water flow, and opens the valve to initiate the flow of brine through the softener ion exchanger :120 to regenerate it. By the time the output segment 64 has been rotated approximately 90 degrees, the drive segment 40 has completed its rotation and its trigger member 53- is projecting radially over the top of the output segment 64. At this point in time, another actuator 114 projecting from the output segment 64 strikes the trigger member 53 on the trigger segment 46 of the control assembly 41 the output segment 64 continues to rotate, the actuator 114 drives the trigger segment 46 of the control assembly 41 into its actuated position across the gap 48 between the ends of the drive segment 40 to engage the rotating control drive pinion 39, which then begins to drive the drive segment 40 through a second rotation.

As the drive segment 40 rotates, the arcuate rack 55 on the collar 54 projecting from the hub 44, which is in engagement with the cam rack 57 on the cam member 56, drives the cam member 56 to its left end position, where it is held by the collar 54 after the arcuate rack 55 has rotated past engagement with the cam rack 57. When the cam member 56 is in that extreme left most position of its reciprocating movement, the sampling intake valve assembly 11 is opened again and the plunger 18 is lifted to the top of its stroke so that it can exert no pressure on the cation exchange resin 2a within the sample sensing chamber 2.

With the sampling intake valve assembly 11 open, ion exchanger regenerating reagent, in this instance brine, that is circulating through the softener tank 6 is also circulated through the sensing ion exchanger 2a in the sensing chamber 2.

This regenerates the sensing ion exchanger 2a to prepare it for the next sensing cycle twenty-four hours later. if a normal flow or regenerating reagent is used for the softener ion-exchange reagent, reagent will flow into the chamber 2 only part of the time when the valve 11 is open, and it will be followed by the sample of soft water that will have resumed its normal flow through the tank 6. The effect of the regenerating reagent on the sensing ion exchanger 2a is to shrink it to its smallest volume, and the subsequent washing with soft water will swell the sensing ion exchanger 2a to its normal maximum volume. If the regenerating cycle is extended, it may happen that the sensing ion exchanger 2a is not washed by soft water before the next sensing cycle. In either case, the condition of the water sample in the next sensing cycle will determine the volume of the sensing ion exchanger 2a so that the softener ion exchanger will be regenerated only if regeneration is necessary to ensure proper operation of the softener.

For the regeneration of the sensing ion exchanger 2a the mechanism follows the same cycle as the original sensing cycle described above. The cam member 56-, after opening the valve 11 returns to the opposite extreme of its reciprocating movement, so that it is to the far right in the drawing. The drive segment 40 of the control mechanism 41 continues rotating until the arcuate rack 55 once again engages the linear cam rack 57 on the cam member 56 and drives the cam member 56 from the right hand extreme of its reciprocating movement back to its normal central position. At that point, the gap 48 between the ends of the drive segment 40 again reaches the control drive pinion 39 to halt the rotation of the drive segment 40, thus ending the entire operating cycle and holding the control mechanism 41 in its normal position until the timing gear 89 initiates the next sampling. In the specific embodiment shown here, the regeneration cycle consumes about 2 /2 hours.

The cam member 56 with the sensing cam surface 83 and the sampling cam surface 96 serves as a means for sequentially, first, introducing a water sample into the chamber 2, and, second, sensing the response of the sensing ion exchanger 2a to detect the hardness of the water. The cam member 56 also normally holds the plunger 18 out of engagement with the sensing resin 2a so that the sensing ion exchanger 2a can seek its proper volume and will not be damaged. Finally the sealing plug 5 may be seen as inner and outer members 101 and 97, respectively, that are assembled in telescoping relationship with a screw thread connection between them as a seal and as means for relatively moving them axially so that the inclined planes of the tapered surfaces 101 and 104 coact to grip or release the tube 3.

The embodiment just described represents the best mode presently contemplated by the inventor for carrying out this invention. However, other embodiments will be developed to meet the needs of other systems and still more embodiments are possible that may not be practiced. Hence, the invention is not to be confused with a specific embodiment of it. The invention itself is particularly pointed out in the claims that follow.

I claim:

1. A process for mechanically detecting ion concentrations in a liquid comprising the steps of placing a measured volume of regenerated ion exchanger that responds to ion concentrations by radical volume changes in a chamber;

washing said ion exchanger with a liquid the ion concentration of which is to be detected;

moving a mechanical sensor in said chamber toward engagement with said ion exchanger;

detecting the distance traveled by said mechanical sensor before reaching engagement with said ion exchanger;

withdrawing said mechanical sensor out of engagement with said ion exchanger;

and washing said ion exchanger with a regenerating reagent to regenerate said ion exchanger.

2. A process as set forth in claim 1 wherein said 13 washings of said ion exchanger are accomplished by directing a flow of liquid transversely through said ion exchanger throughout the entire depth of said ion exchanger.

3. A process for detecting ion concentrations in liquid composing the steps of,

placing a given volume of regenerated ion exchange resin that responds to ion concentrations by a change in its volume in a chamber;

washing said ion exchange resin periodically with a sample of the liquid the ion concentration of which is to be detected;

mechanically engaging said resin in said chamber with a sensor to detect a change in the volume of the resin; and

retracting the sensor after each periodical sensing movement of said sensor.

4. A process for detecting ion concentration in a liquid according to claim 3 wherein the critical level of ion concentration in the liquid is reflected by a reduction in the volume of the resin in said chamber of a predetermined lesser volume,

and said mechanical sensor after each washing of the resin in the chamber senses the volume of the resin in the chamber to determine if a reduction in the vo1- ume of the resin to the predetermined reduced vol ume has occurred; and together with the step of,

washing said ion exchange resin in said chamber after its volume has reduced to the predetermined lesser volume as determined by said sensor with a regenerating reagent to restore it to its original given volume.

References Cited UNITED STATES PATENTS 3,246,759 4/1966 Matalon 210-96 3,250,392 5/1966 Luck 210-25 X 3,578,164 5/1971 Weiss et al. 210-96 JOHN ADEE, Primary Examiner U.S. Cl. X.-R. 210-96 

